Similar happened to me, but I was lucky enough to be parked at BCS getting ready to leave after several days of service. It was closing time, but Ken and a couple techs stayed after to ferret out the problem. As I recall I got a new salesman's switch, and Ken said to leave it in the on position, period. They weren't designed for general owner use to power down the coach, and they don't shut everything off anyway, just some interior circuits. Constant use will wear them out prematurely. Conceivably ditto for the associated latching solenoid.
Ideally, the switch should be removed upon sale of the rig, and the hole capped. Owners can either develop better habits as I subsequently did and cease using it as a convenient battery saver or light control, or they can jumper the wires behind it or, like Jerry perhaps, jumper/join the solenoid large wires. Though they didn't find anything particularly wrong with the latching solenoid hiding on the right wall in the Big Boy/High Amp Fuse box in my situation, Ken had them switch it out anyway.
-Joel